This disclosure generally relates to a process for preparing hydroquinone compounds from aromatic hydroxy compounds.
Hydroquinone compounds find applications in a wide range of industries including, among others, the polymer industry, the dye industry, and the photographic industry as well as in medical applications. They are also known for fabricating polycarbonates for use in liquid crystal displays.
Oxidation of phenol with hydrogen peroxide in the presence of a catalyst to produce dihydric phenol has been studied using a variety of catalysts systems including strong acids and zeolites. However reactions using these catalysts yield mostly ortho dihydric phenols (catechols) with decreased selectivity for para dihydric phenol (hydroquinone) and its derivatives.
A number of attempts have been made to improve reaction selectivity for hydroquinones over catechols in a variety of catalyst systems. However each approach suffers one or more significant drawbacks such as difficulty in separating the catalyst from the product, catalyst cost and environmental concerns regarding one or more components of the reaction system. These drawbacks make these approaches commercially undesirable.
Accordingly, there is a need in the art for a commercial and cost effective process for manufacturing dihydric phenols with improved para selectivity.